Molecular basis of cardioprotective effect of antioxidant vitamins in myocardial infarction

Targeted Antioxidant Therapy Reduces Hyperglycemic Exacerbation of Myocardial Ischemia-Reperfusion

INTRODUCTION

Acute hyperglycemia (HG) enhances inflammatory and oxidative stress and exacerbates myocardial infarct size during ischemia-reperfusion injury by activating splenic leukocytes. Formyl peptide receptor 1 (FPR1) on leukocytes is activated by and mediates myocardial ischemia-reperfusion injury. We hypothesize that selective FPR1 antagonist cinnamoyl-F-(D)L-F-(D)L-F (CF) or potent reducing agent tris (2-carboxyethyl) phosphine hydrochloride (TCEP) could abrogate hyperglycemic infarct exacerbation, both alone and synergistically via a novel CF-TCEP compound that would target leukocytes for antioxidative effect.

METHODS

Acute HG was induced in wild type mice with an intraperitoneal dextrose injection followed by left coronary artery occlusion (30 min) and reperfusion (60 min). In treatment groups, CF (0.1 mg/kg or 1 mg/kg), TCEP (1 mg/kg or 20 mg/kg), or the CF-TCEP conjugate (0.1 mg/kg) was administered intravenously before reperfusion. The hearts were harvested to measure infarct size (IF).

RESULTS

HG resulted in >50% increase in IF compared to euglycemic mice (52.1 ± 3.0 versus 34.0 ± 3.2%, P < 0.05). Neither CF nor TCEP independently exerted an infarct-sparing effect at lower doses (46.2 ± 2.1% or 50.9 ± 4.1%, P > 0.05 versus HG control) but at high doses, significantly attenuated IF exacerbation (23.2 ± 5.2% or 33.9 ± 3.6%, P < 0.05 versus HG control). However, the low-dose CF-TCEP conjugate significantly reduced IF (39.1 ± 1.7%, P < 0.05 versus HG control). IF was decreased to near euglycemic control levels (P > 0.05).

CONCLUSIONS

The CF-TECP conjugate synergistically attenuated HG infarct exacerbation at significantly lower respective doses of CF and TCEP. In addition to the intrinsic anti-inflammatory effect of blocking FPR1, CF is also a feasible tool for leukocyte-targeted therapy to treat IRI.

Effects of electrospun fibers containing ascorbic acid on oxidative stress reduction for cardiac tissue engineering

Tissue engineering provides promise for regeneration of cardiac tissue following myocardial infarction. However, the harsh microenvironment of the infarct hampers the efficacy of regenerative therapies. Ischemia-reperfusion injury dramatically increases the levels of reactive oxygen species (ROS) within the infarcted area, causing a cascade of further cellular injury. Implantable tissue engineered grafts can target this oxidative stress by delivering pharmaceutical compounds directly into the diseased tissue. Herein, we successfully fabricated electrospun polycaprolactone (PCL) fibers containing varying concentrations of ascorbic acid, a potent antioxidant well known for its ROS-scavenging capabilities. The antioxidant scaffolds displayed significantly improved scavenging of DPPH radicals, superoxide anions and hydroxyl radicals, in a dose dependent manner. Mechanical properties testing indicated that incorporation of ascorbic acid enhanced the strength and Young's modulus of the material, correlating with a moderate but non-significant increase in the crystallinity. Moreover, the scaffolds supported adhesion and maintained survival of human umbilical vein endothelial cells in vitro, indicating good cytocompatibility. These results provide motivation for the use of ascorbic acid-containing fibrous scaffolds to regulate the highly oxidative microenvironment following myocardial infarction.

Anti-Inflammatory and Vasorelaxant Effects Induced by an Aqueous Aged Black Garlic Extract Supplemented with Vitamins D, C, and B12 on Cardiovascular System

Multiple studies demonstrated biological activities of aged black garlic, including anti-inflammatory, antioxidant, and cardioprotective effects. We aimed to investigate the protective effects of an aged black garlic water extract (ABGE) alone or in association with multivitamins consisting of combined Vitamins D, C, and B12, on mouse heart specimens exposed to E. coli lipopolysaccharide (LPS). Moreover, we studied the hydrogen sulphide (H₂S) releasing properties and the membrane hyperpolarization effect of the Formulation composed by ABGE and multivitamins, using Human Aortic Smooth Muscle Cells (HASMCs). ABGE, vitamins D and C, and the Formulation suppressed LPS-induced gene expression of cyclooxygenase (COX)-2, tumor necrosis factor (TNF)-α, interleukin (IL)-6, nuclear factor-kB (NF-kB), and inducible nitric oxide synthase (iNOS) on mouse heart specimens. The beneficial effects induced by the extract could be related to the pattern of polyphenolic composition, with particular regard to gallic acid and catechin. The Formulation also increased fluorescence values compared to the vehicle, and it caused a significant membrane hyperpolarization of HASMCs compared to ABGE. To conclude, our present findings showed that ABGE, alone and in association with multivitamins, exhibited protective effects on mouse heart. Moreover, the Formulation increased intracellular H₂S formation, further suggesting its potential use on cardiovascular disease.

Myocardial infarction and oxidative damage in animal models: objective and expectations from the application of cysteine derivatives

Reactive oxygen species (ROS) and associated oxidative stress are the main contributors to pathophysiological changes following myocardial infarction (MI), which is the principal cause of death from cardiovascular disease. The glutathione (GSH)/glutathione peroxidase (GPx) system appears to be the main and most active cardiac antioxidant mechanism. Hence, enhancement of the myocardial GSH system might have protective effects in the setting of MI. It follows that by increasing antioxidant capacity, the heart will be able to reduce the damage associated with MI and even prevent/weaken the occurrence of oxidative stress, which is highly ranked among the factors responsible for the occurrence of acute MI. For these reasons, the primary goal of future investigations should be to address the effects of different antioxidative compounds and especially cysteine derivatives like N-acetyl cysteine (NAC) and L-2-oxothiazolidine-4-carboxylic acid (OTC) as precursors responsible for the enhancement of the GSH-related antioxidant system's capacity. It is assumed that this will lay down the basis for elucidation of the mechanisms throughout which applicable doses of OTC will manifest a potentially positive impact in the reduction of adverse effects of acute MI. The inclusion of OTC in the models for prediction of the distribution of oxygen in infarcted animal hearts can help to upgrade existing computational models. Such a model would be based on computational geometries of the heart, but the inclusion of biochemical redox features in addition to angiogenic therapy, despite improvement of the post-infarcted oxygenated outcome could enhance the accuracy of the predictive values of oxygenation.

Cardioprotective Mechanisms against Reperfusion Injury in Acute Myocardial Infarction: Targeting Angiotensin II Receptors

Ischemia/reperfusion injury is a process associated with cardiologic interventions, such as percutaneous coronary angioplasty after an acute myocardial infarction. Blood flow restoration causes a quick burst of reactive oxygen species (ROS), which generates multiple organelle damage, leading to the activation of cell death pathways. Therefore, the intervention contributes to a greater necrotic zone, thus increasing the risk of cardiovascular complications. A major cardiovascular ROS source in this setting is the activation of multiple NADPH oxidases, which could result via the occupancy of type 1 angiotensin II receptors (AT1R); hence, the renin angiotensin system (RAS) is associated with the generation of ROS during reperfusion. In addition, ROS can promote the expression of NF-κΒ, a proinflammatory transcription factor. Recent studies have described an intracellular RAS pathway that is associated with increased intramitochondrial ROS through the action of isoform NOX4 of NADPH oxidase, thereby contributing to mitochondrial dysfunction. On the other hand, the angiotensin II/ angiotensin type 2 receptor (Ang II/AT2R) axis exerts its effects by counter-modulating the action of AT1R, by activating endothelial nitric oxide synthase (eNOS) and stimulating cardioprotective pathways such as akt. The aim of this review is to discuss the possible use of AT1R blockers to hamper both the Ang II/AT1R axis and the associated ROS burst. Moreover; we suggest that AT1R antagonist drugs should act synergistically with other cardioprotective agents, such as ascorbic acid, N-acetylcysteine and deferoxamine, leading to an enhanced reduction in the reperfusion injury. This therapy is currently being tested in our laboratory and has shown promising outcomes in experimental studies.

Protective Effects of L-2-Oxothiazolidine-4-Carboxylate during Isoproterenol-Induced Myocardial Infarction in Rats: In Vivo Study

This study aimed to evaluate the cardioprotective effects of L-2-oxothiazolidine-4-carboxylate (OTC) against isoproterenol (ISO)-induced acute myocardial infarction (MI) in rats. Results demonstrated that OTC treatments inhibited ISO-induced oxidative damage, suppressed lipid peroxidation, and increased superoxide dismutase and catalase activity in the hearts of the treated rats compared to those of the untreated controls. The ISO-related NF-κB activation was reduced due to the OTC treatment, and lower degrees of inflammatory cell infiltration and necrosis in the hearts were observed. In summary, OTC treatments exerted cardioprotective effects against MI in vivo, mainly due to enhancing cardiac antioxidant activity.

Untargeted Metabolomics Studies of H9c2 Cardiac Cells Submitted to Oxidative Stress, β-Adrenergic Stimulation and Doxorubicin Treatment: Investigation of Cardiac Biomarkers

One of the biggest challenges in the search for more effective treatments for diseases is understanding their etiology. Cardiovascular diseases (CVD) are an important example of this, given the high number of deaths annually. Oxidative stress (the imbalance between oxidant and antioxidant species in biological system) is one of the factors responsible for CVD occurrence, demanding extensive investigation. Excess of reactive oxygen species (ROS) are primarily responsible for this condition, and clinical and scientific literature have reported a significant increase in ROS when therapeutic drugs, such as doxorubicin and isoproterenol, are administered. In this context, the aim of this study is the investigation of potential biomarkers that might be associated with oxidative stress in cardiomyocytes. For this purpose, H9c2 cardiomyocytes were submitted to oxidative stress conditions by treatment with doxorubicin (DOX), isoproterenol (ISO) and hydrogen peroxide (PER). Metabolomics analyses of the cell extract and the supernatant obtained from the culture medium were then evaluated by CE-ESI(+)-TOF-MS. Following signal processing, statistical analyses, and molecular features annotations, the results indicate changes in the aspartate, serine, pantothenic acid, glycerophosphocholine and glutathione metabolism in the cell extract.

Role of Oxidative Stress in Cardiac Dysfunction and Subcellular Defects Due to Ischemia-Reperfusion Injury

Ischemia-reperfusion (I/R) injury is well-known to be associated with impaired cardiac function, massive arrhythmias, marked alterations in cardiac metabolism and irreversible ultrastructural changes in the heart. Two major mechanisms namely oxidative stress and intracellular Ca²⁺-overload are considered to explain I/R-induced injury to the heart. However, it is becoming apparent that oxidative stress is the most critical pathogenic factor because it produces myocardial abnormalities directly or indirectly for the occurrence of cardiac damage. Furthermore, I/R injury has been shown to generate oxidative stress by promoting the formation of different reactive oxygen species due to defects in mitochondrial function and depressions in both endogenous antioxidant levels as well as regulatory antioxidative defense systems. It has also been demonstrated to adversely affect a wide variety of metabolic pathways and targets in cardiomyocytes, various resident structures in myocardial interstitium, as well as circulating neutrophils and leukocytes. These I/R-induced alterations in addition to myocardial inflammation may cause cell death, fibrosis, inflammation, Ca²⁺-handling abnormalities, activation of proteases and phospholipases, as well as subcellular remodeling and depletion of energy stores in the heart. Analysis of results from isolated hearts perfused with or without some antioxidant treatments before subjecting to I/R injury has indicated that cardiac dysfunction is associated with the development of oxidative stress, intracellular Ca²⁺-overload and protease activation. In addition, changes in the sarcolemma and sarcoplasmic reticulum Ca²⁺-handling, mitochondrial oxidative phosphorylation as well as myofibrillar Ca²⁺-ATPase activities in I/R hearts were attenuated by pretreatment with antioxidants. The I/R-induced alterations in cardiac function were simulated upon perfusing the hearts with oxyradical generating system or oxidant. These observations support the view that oxidative stress may be intimately involved in inducing intracellular Ca²⁺-overload, protease activation, subcellular remodeling, and cardiac dysfunction as a consequence of I/R injury to the heart.

Antioxidant Cardioprotection against Reperfusion Injury: Potential Therapeutic Roles of Resveratrol and Quercetin

Ischemia-reperfusion myocardial damage is a paradoxical tissue injury occurring during percutaneous coronary intervention (PCI) in acute myocardial infarction (AMI) patients. Although this damage could account for up to 50% of the final infarct size, there has been no available pharmacological treatment until now. Oxidative stress contributes to the underlying production mechanism, exerting the most marked injury during the early onset of reperfusion. So far, antioxidants have been shown to protect the AMI patients undergoing PCI to mitigate these detrimental effects; however, no clinical trials to date have shown any significant infarct size reduction. Therefore, it is worthwhile to consider multitarget antioxidant therapies targeting multifactorial AMI. Indeed, this clinical setting involves injurious effects derived from oxygen deprivation, intracellular pH changes and increased concentration of cytosolic Ca²⁺ and reactive oxygen species, among others. Thus, we will review a brief overview of the pathological cascades involved in ischemia-reperfusion injury and the potential therapeutic effects based on preclinical studies involving a combination of antioxidants, with particular reference to resveratrol and quercetin, which could contribute to cardioprotection against ischemia-reperfusion injury in myocardial tissue. We will also highlight the upcoming perspectives of these antioxidants for designing future studies.

Coenzyme Q10 Reduces Infarct Size in Animal Models of Myocardial Ischemia-Reperfusion Injury: A Meta-Analysis and Summary of Underlying Mechanisms

Objective

Effective interventions that might limit myocardial ischemia-reperfusion (I/R) injury are still lacking. Coenzyme Q₁₀ (CoQ₁₀) may exert cardioprotective actions that reduce myocardial I/R injury. We conducted this meta-analysis to assess the potential cardioprotective effect of CoQ₁₀ in animal models of myocardial I/R injury.

Methods

We searched PubMed and Embase databases from inception to February 2022 to identify animal studies that compared the effect of CoQ₁₀ with vehicle treatment or no treatment on myocardial infarct size in models of myocardial I/R injury. Means and standard deviations of the infarct size measurements were pooled as the weighted mean difference with 95% confidence interval (CI) using the random-effects model. Subgroup analyses were also conducted according to animals' species, models' type, and reperfusion time.

Results

Six animal studies (4 in vivo and 2 ex vivo) with 116 animals were included. Pooled analysis suggested that CoQ₁₀ significantly reduced myocardial infarct size by −11.36% (95% CI: −16.82, −5.90, p < 0.0001, I² = 94%) compared with the control group. The significance of the pooled effect estimate was maintained in rats, Hartley guinea pigs, and Yorkshire pigs. However, it became insignificant in the subgroup of rabbits −5.29% (95% CI: −27.83, 17.26; I² = 87%). Furthermore, CoQ₁₀ significantly reduced the myocardial infarct size regardless of model type (either in vivo or ex vivo) and reperfusion time (either ≤ 4 h or >4 h).

Conclusion

Coenzyme Q₁₀ significantly decreased myocardial infarct size by 11.36% compared with the control group in animal models of myocardial I/R injury. This beneficial action was retained regardless of model type and reperfusion time.

Comprehending Cardiac Dysfunction by Oxidative Stress: Untargeted Metabolomics of In Vitro Samples

Cardiovascular diseases (CVDs) are noncommunicable diseases known for their complex etiology and high mortality rate. Oxidative stress (OS), a condition in which the release of free radical exceeds endogenous antioxidant capacity, is pivotal in CVC, such as myocardial infarction, ischemia/reperfusion, and heart failure. Due to the lack of information about the implications of OS on cardiovascular conditions, several methodologies have been applied to investigate the causes and consequences, and to find new ways of diagnosis and treatment as well. In the present study, cardiac dysfunction was evaluated by analyzing cells’ alterations with untargeted metabolomics, after simulation of an oxidative stress condition using hydrogen peroxide (H₂O₂) in H9c2 myocytes. Optimizations of H₂O₂ concentration, cell exposure, and cell recovery times were performed through MTT assays. Intracellular metabolites were analyzed right after the oxidative stress (oxidative stress group) and after 48 h of cell recovery (recovery group) by ultra-high-performance liquid chromatography coupled to mass spectrometry (UHPLC-MS) in positive and negative ESI ionization mode. Significant alterations were found in pathways such as “alanine, aspartate and glutamate metabolism”, “glycolysis”, and “glutathione metabolism”, mostly with increased metabolites (upregulated). Furthermore, our results indicated that the LC-MS method is effective for studying metabolism in cardiomyocytes and generated excellent fit (R²Y > 0.987) and predictability (Q² > 0.84) values.

Joint Cardioprotective Effect of Vitamin C and Other Antioxidants against Reperfusion Injury in Patients with Acute Myocardial Infarction Undergoing Percutaneous Coronary Intervention

Percutaneous coronary intervention (PCI) has long remained the gold standard therapy to restore coronary blood flow after acute myocardial infarction (AMI). However, this procedure leads to the development of increased production of reactive oxygen species (ROS) that can exacerbate the damage caused by AMI, particularly during the reperfusion phase. Numerous attempts based on antioxidant treatments, aimed to reduce the oxidative injury of cardiac tissue, have failed in achieving an effective therapy for these patients. Among these studies, results derived from the use of vitamin C (Vit C) have been inconclusive so far, likely due to suboptimal study designs, misinterpretations, and the erroneous conclusions of clinical trials. Nevertheless, recent clinical trials have shown that the intravenous infusion of Vit C prior to PCI-reduced cardiac injury biomarkers, as well as inflammatory biomarkers and ROS production. In addition, improvements of functional parameters, such as left ventricular ejection fraction (LVEF) and telediastolic left ventricular volume, showed a trend but had an inconclusive association with Vit C. Therefore, it seems reasonable that these beneficial effects could be further enhanced by the association with other antioxidant agents. Indeed, the complexity and the multifactorial nature of the mechanism of injury occurring in AMI demands multitarget agents to reach an enhancement of the expected cardioprotection, a paradigm needing to be demonstrated. The present review provides data supporting the view that an intravenous infusion containing combined safe antioxidants could be a suitable strategy to reduce cardiac injury, thus improving the clinical outcome, life quality, and life expectancy of patients subjected to PCI following AMI.

Novel Combined Antioxidant Strategy against Hypertension, Acute Myocardial Infarction and Postoperative Atrial Fibrillation

Reactive oxygen species (ROS) play a physiological role in the modulation of several functions of the vascular wall; however, increased ROS have detrimental effects. Hence, oxidative stress has pathophysiological impacts on the control of the vascular tone and cardiac functions. Recent experimental studies reported the involvement of increased ROS in the mechanism of hypertension, as this disorder associates with increased production of pro-oxidants and decreased bioavailability of antioxidants. In addition, increased ROS exposure is found in ischemia-reperfusion, occurring in acute myocardial infarction and cardiac surgery with extracorporeal circulation, among other settings. Although these effects cause major heart damage, at present, there is no available treatment. Therefore, it should be expected that antioxidants counteract the oxidative processes, thereby being suitable against cardiovascular disease. Nevertheless, although numerous experimental studies agree with this notion, interventional trials have provided mixed results. A better knowledge of ROS modulation and their specific interaction with the molecular targets should contribute to the development of novel multitarget antioxidant effective therapeutic strategies. The complex multifactorial nature of hypertension, acute myocardial infarction, and postoperative atrial fibrillation needs a multitarget antioxidant strategy, which may give rise to additive or synergic protective effects to achieve optimal cardioprotection.

Targeting Ferroptosis against Ischemia/Reperfusion Cardiac Injury

Ischemic heart disease is a leading cause of death worldwide. Primarily, ischemia causes decreased oxygen supply, resulting in damage of the cardiac tissue. Naturally, reoxygenation has been recognized as the treatment of choice to recover blood flow through primary percutaneous coronary intervention. This treatment is the gold standard therapy to restore blood flow, but paradoxically it can also induce tissue injury. A number of different studies in animal models of acute myocardial infarction (AMI) suggest that ischemia-reperfusion injury (IRI) accounts for up to 50% of the final myocardial infarct size. Oxidative stress plays a critical role in the pathological process. Iron is an essential mineral required for a variety of vital biological functions but also has potentially toxic effects. A detrimental process induced by free iron is ferroptosis, a non-apoptotic type of programmed cell death. Accordingly, efforts to prevent ferroptosis in pathological settings have focused on the use of radical trapping antioxidants (RTAs), such as liproxstatin-1 (Lip-1). Hence, it is necessary to develop novel strategies to prevent cardiac IRI, thus improving the clinical outcome in patients with ischemic heart disease. The present review analyses the role of ferroptosis inhibition to prevent heart IRI, with special reference to Lip-1 as a promising drug in this clinicopathological context.

Mitochondrial redox and TCA cycle metabolite signaling in the heart

Mitochondria are essential signaling organelles that regulate a broad range of cellular processes and thereby heart function. Multiple mechanisms participate in the communication between mitochondria and the nucleus that maintain cardiomyocyte homeostasis, including mitochondrial reactive oxygen species (ROS) and metabolic shifts in TCA cycle metabolite availability. An increased rate of ROS generation can cause irreversible damage to the cell and proposed to be a leading cause of many pathologies, including accelerated aging and heart disease. Myocardial impairments are also characterised by specific coordinated metabolic changes and dysregulated inflammatory responses. Hence, the mitochondrial respiratory chain is an important mediator between health and disease in the heart. This review will first outline the sources of ROS in the heart, mitochondrial metabolite dynamics, and provide an overview of their implications for heart disease. In addition, we will concentrate our discussion around current cardioprotective strategies relevant to mitochondrial ROS. Thorough understanding of mitochondrial signaling and the complex interplay with vital signaling pathways in the heart might allow us to develop novel therapeutic approaches to cardiovascular disease.

Avoid the trap: Targeting PARP1 beyond human malignancy

PARP1 is a poly(ADP-ribose) polymerase (PARP) enzyme that plays a critical role in regulating DNA damage response. The main enzymatic function of PARP1 is to catalyze a protein post-translational modification known as poly(ADP-ribosyl)ation (PARylation). Human cancers with homologous recombination deficiency are highly sensitive to PARP1 inhibitors. PARP1 is aberrantly activated in many non-oncological diseases, leading to the excessive NAD⁺ depletion and PAR formation, thus causing cell death and tissue damage. PARP1 deletion offers a profound protective effect in the relevant animal models. However, many of the current PARP1 inhibitors also induce PARP1 trapping, which drives subsequent DNA damage, innate immune response and cytotoxicity. This minireview provides an overview of the basic biology of PARP1 trapping, and its implications in disease. Furthermore, we also discuss the recent development of PARP1 PROTAC compounds, and their utility as "non-trapping" PARP1 degraders for the potential amelioration of non-oncological diseases driven by aberrant PARP1 activation.

Transient and Stable Overexpression of Extracellular Superoxide Dismutase Is Positively Associated with the Myogenic Function of Human Skeletal Muscle-Derived Stem/Progenitor Cells

In the present study, the genetic modification of human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) was investigated to identify the optimal protocol for myogenic cell preparation for use in post-infarction heart therapy. We used two types of modifications: GFP-transfection (using electroporation) and SOD3 transduction (using a lentiviral vector). SkMDS/PCs were cultured under different in vitro conditions, including standard (21% oxygen) and hypoxic (3% oxygen), the latter of which corresponded to the prevailing conditions in the post-infarction heart. Transfection/transduction efficacy, skeletal myogenic cell marker expression (CD56), cellular senescence, and apoptosis, as well as the expression of antioxidant (SOD1, SOD2, and SOD3), anti-aging (SIRT1 and FOXO), anti-apoptotic (BCL2), and myogenic (MyoD and MyoG) genes, were evaluated. The percentage of GFP-positive SkMDS/PCs was determined as an indicator of the efficacy of transfection, which reached 55%, while transduction showed better efficiency, reaching approximately 85% as estimated by fluorescence microscopy. The CD56-positive SkMDS/PCs were present in approximately 77% of the tested cells after transient transfection and approximately 96% after transduction. Under standard in vitro culture conditions, the ability of the differentiated, transfected SkMDS/PCs to form myotubes was greater than that of the wild type (WT) cell population (p < 0.001), while the cells transduced with the SOD3 gene exhibited an increase in cell fusion under both standard (p < 0.05) and hypoxic conditions (p < 0.001). In transduced SkMDS/PCs, we observed a positive influence of SOD3 overexpression on cell ageing and apoptosis. We observed an increase in the percentage of young cells under standard (p < 0.05) and hypoxic (p < 0.001) in vitro culture conditions, with a notable decrease in the percentage of senescent and advanced senescent cells in the SOD3-overexpressing cell population detected compared to that observed for the untransduced muscle-derived cells. A lower percentage of apoptotic cells was observed for transduced SkMDS/PCs than that for WT cells under hypoxic in vitro culture conditions. In transiently transfected SkMDS/PCs, we observed significantly higher gene expression levels of SOD2 (almost 40-fold) (p < 0.001) and FOXO (p < 0.05) (approximately 3-fold) under both normoxic and hypoxic culture conditions and of BCL2 under hypoxia compared to those observed in untreated cells (WT). In addition, myogenic genes showed a significant increase in MyoD (almost 18-fold) expression under standard culture conditions (p < 0.0001) and decreased MyoG expression (approximately 2-fold) after transfection (p < 0.05) compared with that detected in the WT skeletal muscle-derived cell control. Taken together, these results demonstrate that SOD3-tranduced skeletal muscle-derived cells may have potential for use in the regenerative treatment of the post-infarction heart.

Therapeutic Efficacy of Alpha-Lipoic Acid against Acute Myocardial Infarction and Chronic Left Ventricular Remodeling in Mice

Background

We hypothesized that daily administration of a potent antioxidant (α-lipoic acid: ALA) would protect the heart against both acute myocardial infarction (AMI) and left ventricular remodeling (LVR) post-AMI.

Methods and Results

Two separate studies were conducted. In the AMI study, C57Bl/6 mice were fed ALA daily for 7 d prior to a 45-minute occlusion of the left coronary artery (LCA). Mean infarct size in control mice (fed water) was 60 ± 2%. Mean infarct size in ALA-treated mice was 42 ± 3% in the 15 mg/kg·d group and 39 ± 3% in the 75 mg/kg·d group (both P < 0.05 vs. control). In the LVR study, AMI increased LV end-systolic volume (LVESV) and reduced LV ejection fraction (LVEF) to a similar extent in both groups when assessed by cardiac MRI 1 day after a 2-hour LCA occlusion. Treatment with ALA (75 mg/kg·d) or H₂O was initiated 1 day post-AMI and continued until study's end. Both LVESV and LVEF in ALA-treated mice were significantly improved over control when assessed 28 or 56 days post-AMI. Furthermore, the survival rate in ALA-treated mice was 63% better than in control mice by 56 days post-AMI.

Conclusions

Daily oral ingestion of ALA not only protects mice against AMI but also attenuates LVR and preserves contractile function in the months that follow.

Pathophysiology and diagnosis of coronary microvascular dysfunction in ST-elevation myocardial infarction

Early mechanical reperfusion of the epicardial coronary artery by primary percutaneous coronary intervention (PCI) is the guideline-recommended treatment for ST-elevation myocardial infarction (STEMI). Successful restoration of epicardial coronary blood flow can be achieved in over 95% of PCI procedures. However, despite angiographically complete epicardial coronary artery patency, in about half of the patients perfusion to the distal coronary microvasculature is not fully restored, which is associated with increased morbidity and mortality. The exact pathophysiological mechanism of post-ischaemic coronary microvascular dysfunction (CMD) is still debated. Therefore, the current review discusses invasive and non-invasive techniques for the diagnosis and quantification of CMD in STEMI in the clinical setting as well as results from experimental in vitro and in vivo models focusing on ischaemic-, reperfusion-, and inflammatory damage to the coronary microvascular endothelial cells. Finally, we discuss future opportunities to prevent or treat CMD in STEMI patients.

The long noncoding RNA NKILA protects against myocardial ischaemic injury by enhancing myocardin expression via suppressing the NF-κB signalling pathway

BACKGROUND

The lncRNA NKILA has been reported to interact with NF-κB and has an important role in various human diseases. However, the role of NKILA in myocardial ischaemic injury is still unknown.

METHODS

We established cell and animal models of myocardial ischaemic injury. We confirmed our findings by overexpressing NKILA, silencing myocardin and using an NF-κB pathway inhibitor in a hypoxia/reoxygenation (H/R) model of H9c2 cells. An animal model of ischaemia-reperfusion (I/R) injury was established by LAD ligation. Overexpression of NKILA was achieved by adeno-associated virus (AAV) injection through the tail vein. Annexin-V/PI staining and flow cytometric analysis were performed to test cell apoptosis. ELISAs were used to determine the secretion of inflammatory factors. TTC, HE and TUNEL staining were performed to study myocardial pathological injury. qRT-PCR or Western blotting were used to test the expression levels of NKILA, myocardin, the NF-κB pathway and apoptosis-related proteins.

RESULTS

H/R and I/R treatment significantly suppressed the expression of NKILA and activated the NF-κB pathway, resulting in the loss of myocardin. Overexpressing NKILA led to the suppression of the NF-κB pathway and successfully prevented the cell apoptosis and inflammatory responses caused by H/R stimulation in H9c2 cells. Silencing myocardin reversed the protective effect of NKILA and led to severe injury in the H9c2 cells that underwent H/R. Furthermore, the NF-κB pathway inhibitor BAY11-7028 reduced the H/R injury in H9c2 cells with little effect on NKILA expression. Similar results were confirmed in an animal model of myocardial I/R injury and showed that overexpression of NKILA inhibited I/R-triggered myocardial injury in vivo.

CONCLUSION

NKILA enhanced the expression of myocardin via inhibiting the NF-κB signalling pathway and preventing cell apoptosis and the inflammatory response of cardiomyocytes, thus ameliorating myocardial I/R injury.

Protective Effect Of Vasicine Against Myocardial Infarction In Rats Via Modulation Of Oxidative Stress, Inflammation, And The PI3K/Akt Pathway

Background

Myocardial infarction is the leading cause of damage to the heart and is classified as a major cause of death related to cardiovascular disease. In the present study, we intended to investigate the protective effect of vasicine (VAS) against myocardial infarction in rats, and its mechanism.

Methods

Myocardial infarction was induced by isoproterenol (ISO, 100 mg/kg) at an interval of 24 h for 2 days. Different doses of VAS (2.5, 5, and 10 mg/kg body weight) were administered to the rats. The effect of VAS on oxidative stress markers such as, myocardial necrosis, myocardial ability and infarct volume, inflammatory cytokines, membrane-bound myocardial enzymes, and histopathological changes was investigated. Western blot analysis was also conducted to analyze the effect of VAS on autophagy (PI3K/Akt) and apoptosis (Bcl-2, Bax, and caspase-3). The number of apoptotic cells in the different groups was also identified using TUNEL.

Results

Results suggested that VAS causes reduction in myocardial necrosis by reduction of elevated LDH, CK-MB, and TnT levels. It also causes augmentation of left ventricular systolic pressure (LVSP) and myocardial contractility as determined in terms of +dp/dt_max and –dp/dt_max. Furthermore, VAS causes reduction of TNF-α and IL-6 levels. VAS also improved cardiac function via enhancing posterior wall thickness of the LV with concurrent increase in the mass of LV. In the present study, VAS caused activation of phosphorylated PI3K (p-PI3K) and phosphorylated Akt (p-Akt) in a dose-dependent manner. Furthermore, VAS suppressed apoptosis when tested on animals suffering from ISO-induced MI, by decreasing the expression of cleaved Caspase-3 and Bax while increasing the expression of Bcl-2.

Conclusion

In conclusion, vasicine has a protective effect against MI in vivo, through inhibiting oxidative stress, inflammation and excessive autophagy, to suppress apoptosis via activation of the PI3K/Akt/mTOR signaling pathway.

Cyclic enaminone as new chemotype for selective cyclooxygenase-2 inhibitory, anti-inflammatory, and analgesic activities

The cyclic enaminone moiety has been identified as a new scaffold for selective inhibition of cyclooxygenase-2 with anti-inflammatory and analgesic activities. The designed cyclic enaminones have been synthesized conveniently through the development of a new catalyst-free methodology and evaluated for cyclooxygenase (COX-1 and COX-2) inhibitory activities. Three compounds 7d, 8, and 9 predominantly inhibited COX-2 with selectivity index of 74.09, 19.45 and 108.68, respectively, and were assessed for in vivo anti-inflammatory activity in carrageenan induced rat paw edema assay. The anti-inflammatory activity of 7d was comparable to that of celecoxib at a dose of 12.5 mg/kg. However, the compounds 8 and 9 were more/equally effective as anti-inflammatory agent compared to celecoxib at the doses of 12.5 mg/kg and 25 mg/kg and also exhibited anti-inflammatory activity comparable to that of diclofenac. The therapeutic potential of the most active compound 9 was further assessed by performing in vivo thermal and mechanical hyperalgesia tests using various models that revealed its analgesic activity. The in vivo non-ulcerogenicity of 9 revealed the gastrointestinal safety as compared to the non-selective COX inhibitor indomethacin. The in vitro antioxidant activity and in vivo experiments on heart rate and blood pressure provided the cardiovascular safety profile of 9. The molecular docking studies rationalize the COX-2 selectivity of the newly found anti-inflammatory compounds 7d, 8, and 9.

Role of MAPK/NF-κB pathway in cardioprotective effect of Morin in isoproterenol induced myocardial injury in rats

Oxidative stress plays a major role in myocardial injury. Morin, a bioflavonoid has known to possess various biological activities in previous studies. Hence, this study evaluated the cardioprotective mechanism(s) of Morin against isoproterenol induced myocardial necrosis in rats. Male albino Wistar rats were divided into five groups (n = 8) i.e., I (normal), II (ISO-control), III, IV and V (morin 20, 40 and 80 mg/kg respectively). Groups III, IV and V were treated orally with daily doses of Morin accordingly for 28 days. On 26th and 27th day, a single injection of isoproterenol was injected (85 mg/kg s.c.) at 24 h interval to induce myocardial necrosis in group II, III, IV and V. On 28th day, hemodynamic parameters were evaluated, animals were euthanised and heart was excised for measurement of various parameters. In ISO-control rats, there was deterioration of hemodynamic parameters, decreased anti-oxidants levels, increased cardiac injury markers and pro-inflammatory cytokines (TNF-α and IL-6). Also, there was increased level of Bax, Caspase-3, p-JNK, p-38 and NF-κB and decreased expression of Bcl-2 and p-ERK1/2 in ISO-C group. Morin dose-dependently improved hemodynamic profile, increased anti-oxidant levels, normalized myocardial architecture and reduced inflammatory markers and apoptosis. Furthermore, immunoblot analysis of MAPK pathway proteins demonstrated the mechanism responsible for anti-apoptotic and anti-inflammatory potential of morin. Thus, this study substantiated the beneficial effect of Morin by virtue of its modulation of MAPK pathway in myocardial injury.

Myocardial reperfusion injury and oxidative stress: Therapeutic opportunities

Acute myocardial infarction (AMI) is the leading cause of death worldwide. Its associated mortality, morbidity and complications have significantly decreased with the development of interventional cardiology and percutaneous coronary angioplasty (PCA) treatment, which quickly and effectively restore the blood flow to the area previously subjected to ischemia. Paradoxically, the restoration of blood flow to the ischemic zone leads to a massive production of reactive oxygen species (ROS) which generate rapid and severe damage to biomolecules, generating a phenomenon called myocardial reperfusion injury (MRI). In the clinical setting, MRI is associated with multiple complications such as lethal reperfusion, no-reflow, myocardial stunning, and reperfusion arrhythmias. Despite significant advances in the understanding of the mechanisms accounting for the myocardial ischemia reperfusion injury, it remains an unsolved problem. Although promising results have been obtained in experimental studies (mainly in animal models), these benefits have not been translated into clinical settings. Thus, clinical trials have failed to find benefits from any therapy to prevent MRI. There is major evidence with respect to the contribution of oxidative stress to MRI in cardiovascular diseases. The lack of consistency between basic studies and clinical trials is not solely based on the diversity inherent in epidemiology but is also a result of the methodological weaknesses of some studies. It is quite possible that pharmacological issues, such as doses, active ingredients, bioavailability, routes of administration, co-therapies, startup time of the drug intervention, and its continuity may also have some responsibility for the lack of consistency between different studies. Furthermore, the administration of high ascorbate doses prior to reperfusion appears to be a safe and rational therapy against the development of oxidative damage associated with myocardial reperfusion. In addition, the association with N-acetylcysteine (a glutathione donor) and deferoxamine (an iron chelator) could improve the antioxidant cardioprotection by ascorbate, making it even more effective in preventing myocardial reperfusion damage associated with PCA following AMI.

Immunomodulatory interventions in myocardial infarction and heart failure: a systematic review of clinical trials and meta-analysis of IL-1 inhibition

Following a myocardial infarction (MI), the immune system helps to repair ischaemic damage and restore tissue integrity, but excessive inflammation has been implicated in adverse cardiac remodelling and development towards heart failure (HF). Pre-clinical studies suggest that timely resolution of inflammation may help prevent HF development and progression. Therapeutic attempts to prevent excessive post-MI inflammation in patients have included pharmacological interventions ranging from broad immunosuppression to immunomodulatory approaches targeting specific cell types or factors with the aim to maintain beneficial aspects of the early post-MI immune response. These include the blockade of early initiators of inflammation including reactive oxygen species and complement, inhibition of mast cell degranulation and leucocyte infiltration, blockade of inflammatory cytokines, and inhibition of adaptive B and T-lymphocytes. Herein, we provide a systematic review on post-MI immunomodulation trials and a meta-analysis of studies targeting the inflammatory cytokine Interleukin-1. Despite an enormous effort into a significant number of clinical trials on a variety of targets, a striking heterogeneity in study population, timing and type of treatment, and highly variable endpoints limits the possibility for meaningful meta-analyses. To conclude, we highlight critical considerations for future studies including (i) the therapeutic window of opportunity, (ii) immunological effects of routine post-MI medication, (iii) stratification of the highly diverse post-MI patient population, (iv) the potential benefits of combining immunomodulatory with regenerative therapies, and at last (v) the potential side effects of immunotherapies.

Engineering Bioinspired Antioxidant Materials Promoting Cardiomyocyte Functionality and Maturation for Tissue Engineering Application

Oxidative stress plays an important role in various pathological conditions, such as wound healing, inflammation, myocardial infarction, and biocompatibility of the materials. Antioxidant polymers to attenuate oxidative stress is an emerging field of biomaterial research with a huge impact in the field of tissue engineering and regenerative medicine. We describe here the fabrication and evaluation of an elastomeric antioxidant polyurethane (PUAO) for tissue engineering applications. Uniaxial and cyclic tensile testing, thermal analysis, degradation, cytotoxicity and antioxidant analysis was carried out. An in vitro oxidative stress model demonstrated that PUAO reduced intracellular oxidative stress in H9C2 cardiomyocytes (p < 0.05) and attenuated reactive oxygen species (ROS) induced cell death (p < 0.001). Under simulated ischemic reperfusion, PUAO could rescue hypoxia induced cell death. Further as a proof of concept, neonatal rat cardiomyocytes cultured on PUAO film displayed synchronous beating with mature phenotype showing expression of cardiac specific α-actinin, troponin-T, and connexin-43 proteins. Intracellular calcium transients established the functionality of cultured cardiomyocytes on PUAO film. Our study demonstrated the potential of this biomaterial to be developed into tissue engineered scaffold to attenuate oxidative stress for treatment of diseased conditions with increased oxidative stress, such as cardiovascular diseases, chronic wound healing, and myocardial infarction.

The effects of percutaneous transluminal coronary intervention on biomarkers of oxidative stress in the erythrocytes of elderly male patients

OBJECTIVES

Oxidative stress plays a key role in the pathogenesis of coronary artery disease. The aim of this study was to compare the effects of percutaneous transluminal coronary angioplasty (PTCA) and elective coronary angiography (EC) on erythrocytic antioxidant defense in elderly male patients.

METHODS

Twenty-three stable angina pectoris (SAP) patients undergoing PTCA and 18 patients with ischemic symptoms scheduled to undergo diagnostic EC were included in the study. The concentrations of malondialdehyde (MDA) and reduced glutathione (GSH) and the activities of Zn,Cu-superoxide dismutase (SOD-1), catalase (CAT), and cytosolic glutathione peroxidase (GSH-Px) were examined in the erythrocytes before, immediately after and 2 weeks following PTCA or EC.

RESULTS

The MDA concentrations were significantly higher and SOD-1, CAT, and GSH-Px activities were significantly lower in the PTCA group than in the EC group at baseline. Two weeks after treatment, the activities of the enzymes significantly increased in both groups, whereas the MDA concentrations decreased only in the PTCA patients.

CONCLUSIONS

The results confirm that an advanced state of atherosclerosis is related to greater levels of oxidative stress. The study indicates that both procedures may induce antioxidant defenses; however, PTCA exclusively induces a long-term reduction in lipid peroxidation.

Effects of a novel ascorbate-based protocol on infarct size and ventricle function in acute myocardial infarction patients undergoing percutaneous coronary angioplasty

INTRODUCTION

This study was designed to test the hypothesis that high-dose ascorbate prior to reperfusion followed by low chronic oral doses ameliorate myocardial reperfusion injury (MRI) in acute myocardial infarction patients subjected to primary percutaneous coronary angioplasty (PCA).

MATERIAL AND METHODS

A randomized double-blind placebo-controlled and multicenter clinical trial was performed on acute myocardial infarction (AMI) patients who underwent PCA. Sodium ascorbate (320 mmol/l, n = 53) or placebo (n = 46) was infused 30 min prior to PCA. Blood samples were drawn at enrolment (M1), after balloon deflation (M2), 6-8 h after M2 (M3) and at discharge (M4). Total antioxidant capacity of plasma (ferric reducing ability of plasma - FRAP), erythrocyte reduced glutathione (GSH) and plasma ascorbate levels were determined in blood samples. Cardiac magnetic resonance (CMR) was performed at 7-15 days and 2-3 months following PCA. Ninety-nine patients were enrolled. In 67 patients, the first CMR was performed, and 40 patients completed follow-up.

RESULTS

The ascorbate group showed significantly higher ascorbate and FRAP levels and a decrease in the GSH levels at M2 and M3 (p < 0.05). There were no significant differences in the infarct size, indexed end-systolic volume and ejection fraction at both CMRs. There was a significant amelioration in the decreased ejection fraction between the first and second CMR in the ascorbate group (p < 0.05).

CONCLUSIONS

Ascorbate given prior to reperfusion did not show a significant difference in infarct size or ejection fraction. However, it improved the change in ejection fraction determined between 7-15 days and 2-3 months. This result hints at a possible functional effect of ascorbate to ameliorate MRI.

Amelioration of persistent left ventricular function impairment through increased plasma ascorbate levels following myocardial infarction

PURPOSE

Percutaneous coronary angioplasty (PCA) has been demonstrated to reduce mortality and morbidity and thereby improve the prognosis of patients undergoing acute myocardial infarctions (AMIs). However, this procedure paradoxically increases the initial damage as the result of a condition known as 'myocardial reperfusion injury'. Oxidative stress may contribute to the mechanism of this injury. The goal of the present study was to ascertain whether high plasma ascorbate levels could ameliorate the reperfusion injuries that occur after the successful restoration of blood flow.

METHODS

Patients from three clinical centers of the public health system were included in the study. The groups were formed by either-sex patients with a diagnosis of ST-segment elevation myocardial infarction with an indication for primary PCA. Only the patients who presented with their first myocardial infarction were enrolled. Ascorbate was administered through an infusion given prior to the restoration of the coronary flow, which was then followed by oral treatment with vitamin C (500 mg/12 hours) plus vitamin E (400 IU/day) for 84 days. The left ventricular ejection fraction (LVEF) was determined by using cardiac magnetic resonance on days 6 and 84 following the onset of the reperfusion. In addition, the microvascular function was assessed by an angiographic evaluation using the Thrombolysis In Myocardial Infarction (TIMI) myocardial perfusion grade (TMPG). The results were grouped according to the plasma ascorbate concentration achieved immediately following the onset of reperfusion into either the HA group (high ascorbate, >1 mmol/l) or the LA group (low ascorbate, <1 mmol/l). The biochemical parameters were analyzed throughout the protocol.

RESULTS

The LVEF of the HA group was significantly higher than that of the LA group, values on day 84 in the HA group were 33% higher than those of the LA group. The amelioration of the LVEF was accompanied by an improvement in the microvascular dysfunction, after PCA, 95% of the patients in the HA group achieved a TMPG of 2-3, in the LA group only 79% of patients showed a TMPG of 2-3.

CONCLUSIONS

These data are consistent with the protective effect of high plasma levels of ascorbate against the oxidative challenge caused by reperfusion injury in patients subjected to PCA following an AMI. Further studies are needed to elucidate the mechanism accounting for this beneficial antioxidant effect.

Oxidative Stress Genes, Antioxidants and Coronary Artery Disease in Type 2 Diabetes Mellitus

The worldwide increasing prevalence of obesity and sedentary lifestyle is the main cause of the rising incidence of T2DM. Due to chronic macrovascular and microvascular complications, T2DM represent a huge socioeconomic burden in the world. Oxidative stress is a key pathogenic mechanism implicated in diabetic coronary artery disease (CAD). Polymorphisms of oxidative stress genes are known to influence oxidative stress levels and are therefore thought to impact CAD pathogenesis. Identifying higher risk groups would be rational, since it would allow better sample selection and thus better results in antioxidant trials. In this review, we summarize the evidence of oxidative stress gene polymorphisms related to the pathogenesis of CAD. Moreover, we provide a review of antioxidants tested in subjects with CAD.

Methane attenuates myocardial ischemia injury in rats through anti-oxidative, anti-apoptotic and anti-inflammatory actions

Myocardial infarction (MI) remains the most frequent cardiovascular disease with high mortality. Recently, methane has been shown protective effects on small intestinal ischemia-reperfusion injury. We hypothesized that methane-rich saline (MS) could protect the myocardium again MI via its anti-oxidative, anti-apoptotic and anti-inflammatory effects. In experiment 1, tetrazolium chloride staining and detection of myocardial enzymes and oxidative and inflammatory parameters were performed at 12h after MI to determine the optimal dose at which intraperitoneal MS exerted the best protective effects on MI. In experiment 2, rats were treated with 10 ml/kg MS. Myocyte apoptosis was detected 72 h after MI, and cardiac function and myocardial remodeling were evaluated 4 weeks after MI. Results showed different dose of MS reduced infarct area, decreased myocardial enzymes, inhibited inflammation and oxidative stress following MI. The optimal dose of MS was 10 mg/kg. Moreover, treatment with 10mg/kg MS for 3 days significantly reduced myocyte apoptosis, improved cardiac function and inhibited myocardial remodeling (reduced anterior wall thickness, attenuated myocyte hypertrophy, and decreased myocardial collagen). MS protects the myocardium of MI rats via its anti-oxidative, anti-inflammatory, anti-apoptotic and anti-remodeling activities. Thus, MS provides a novel and promising strategy for the treatment of ischemic heart diseases.

Role of Opioid Receptors Signaling in Remote Electrostimulation--Induced Protection against Ischemia/Reperfusion Injury in Rat Hearts

Aims

Our previous studies demonstrated that remote electro-stimulation (RES) increased myocardial GSK3 phosphorylation and attenuated ischemia/ reperfusion (I/R) injury in rat hearts. However, the role of various opioid receptors (OR) subtypes in preconditioned RES-induced myocardial protection remains unknown. We investigated the role of OR subtype signaling in RES-induced cardioprotection against I/R injury of the rat heart.

Methods & Results

Male Spraque-Dawley rats were used. RES was performed on median nerves area with/without pretreatment with various receptors antagonists such as opioid receptor (OR) subtype receptors (KOR, DOR, and MOR). The expressions of Akt, GSK3, and PKCε expression were analyzed by Western blotting. When RES was preconditioned before the I/R model, the rat's hemodynamic index, infarction size, mortality and serum CK-MB were evaluated. Our results showed that Akt, GSK3 and PKCε expression levels were significantly increased in the RES group compared to the sham group, which were blocked by pretreatment with specific antagonists targeting KOR and DOR, but not MOR subtype. Using the I/R model, the duration of arrhythmia and infarct size were both significantly attenuated in RES group. The mortality rates of the sham RES group, the RES group, RES group + KOR antagonist, RES group + DOR/MOR antagonists (KOR left), RES group + DOR antagonist, and RES group + KOR/MOR antagonists (DOR left) were 50%, 20%, 67%, 13%, 50% and 55%, respectively.

Conclusion

The mechanism of RES-induced myocardial protection against I/R injury seems to involve multiple target pathways such as Akt, KOR and/or DOR signaling.

Compatibility of Astragalus and Salvia extract inhibits myocardial fibrosis and ventricular remodeling by regulation of protein kinase D1 protein

AIMS

This study is to determine the effect of astragalus and salvia extract on the alteration of myocardium in a rat model of myocardial infarction.

METHODS

A total of 40 male Sprague-Dawley rats were randomly divided into the sham-operated group, the control group, the Astragalus group, the Salvia group, and the compatibility of Astragalus and Salvia and group. The cardiac functions were determined at 8 weeks after treatment. Hematoxylin-eosin staining was performed to observe the morphology and arrangement of cardiomyocytes. Masson's trichrome staining was performed to investigate the distribution of myocardial interstitial collagen. Immunohistochemical staining was performed to determine the expression ofprotein kinase D1 in myocardial tissues.

RESULTS

In the sham-operated group, the Astragalus group, the Salvia group, and the compatibility of Astragalus and Salvia group, the left ventricular systolic pressure and the maximum rate of left ventricular pressure were significantly increased while the left ventricular end diastolic pressure were significantly decreased when compared with those in the control group (P < 0.05). Normal morphology and arrangement of cardiomyocytes were maintained in the compatibility of Astragalus and Salvia group. Contents of collagen fibers in myocardial tissues were decreased in the compatibility of Astragalus and Salvia group (P < 0.05). Expression levels of protein kinase D1 were significantly decreased in cardiomyocytes of the compatibility of Astragalus and Salvia group.

CONCLUSIONS

Compatibility of Astragalus and Salvia extract may inhibit myocardial fibrosis and ventricular remodeling by regulation of protein kinase D1 protein in a rat model of myocardial infarction.

Picroside Ⅱ inhibits hypoxia/reoxygenation-induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in reactive oxygen species production

Reactive oxygen species (ROS)‑induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside Ⅱ, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)‑induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside Ⅱ on H/R‑induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside Ⅱ (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside Ⅱ markedly inhibited H/R‑induced cardiomyocyte apoptosis. In addition, picroside Ⅱ was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase‑3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside Ⅱ inhibited H/R‑induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production.

The effectiveness of antioxidant vitamins C and E in reducing myocardial infarct size in patients subjected to percutaneous coronary angioplasty (PREVEC Trial): study protocol for a pilot randomized double-blind controlled trial

BACKGROUND

Acute myocardial infarction (AMI) is the leading cause of mortality worldwide. Oxidative stress has been involved in the ischemia-reperfusion injury in AMI. It has been suggested that reperfusion accounts for up to 50% of the final size of a myocardial infarct, a part of the damage likely to be prevented.Therefore, we propose that antioxidant reinforcement through vitamins C and E supplementation should protect against the ischemia-reperfusion damage, thus decreasing infarct size.The PREVEC Trial (Prevention of reperfusion damage associated with percutaneous coronary angioplasty following acute myocardial infarction) seeks to evaluate whether antioxidant vitamins C and E reduce infarct size in patients subjected to percutaneous coronary angioplasty after AMI.

METHODS/DESIGN

This is a randomized, 1:1, double-blind, placebo-controlled clinical trial.The study takes place at two centers in Chile: University of Chile Clinical Hospital and San Borja Arriarán Clinical Hospital.The subjects will be 134 adults with acute myocardial infarction with indication for percutaneous coronary angioplasty.This intervention is being performed as a pilot study, involving high-dose vitamin C infusion plus oral administration of vitamin E (Vitamin-treatment group) or placebo (Control group) during the angioplasty procedure. Afterward, the Vitamin-treatment group receives oral doses of vitamins C and E, and the Control group receives placebo for 84 days after coronary angioplasty.Primary outcome is infarct size, assessed by cardiac magnetic resonance (CMR), measured 6 and 84 days after coronary angioplasty.Secondary outcomes are ejection fraction, measured 6 and 84 days after coronary angioplasty with CMR, and biomarkers for oxidative stress, antioxidant status, heart damage, and inflammation, which will be measured at baseline, at the onset of reperfusion, 6 to 8 hours after revascularization, and at hospital discharge.

DISCUSSION

The ischemia-reperfusion event occurring during angioplasty is known to increase myocardial infarct size. The cardioprotective benefits of high doses of vitamin C combined with vitamin E have not been fully explored. The PREVEC Trial seeks to determine the suitability of the therapeutic use of vitamins C and E against the reperfusion damage produced during angioplasty.Patient recruitment opened in February 2013. The trial is scheduled to end in March 2016.

TRIAL REGISTRATION

ISRCTN56034553.